2003 Toyota Highlander Noisy ride

Seems like the last time I had the tires rotated there's been excessive cabin noise. A friend suggested the differential might be going. One mechanic told me the tires on the vehicle were heavy duty truck tires and that's why it was loud. Any ideas on what it may be? Tires are in great shape, no excessive wear, it doesn;t pull to either side, no rattles or shakes. Hmmmm?